No net external torque --> no change in angular momentum
No net external force --> no change in linear momentum
After ball tossed it has momentum toward back so the boat must have forward momentum to maintain the zero initial momentum.
After the catch both the ball and boat the two must be at the same speed and this must be at rest to have momentum zero as it was originally
- Neither the mass, M, nor the spring constant, k, depend on the gravitational force of the planet.
The path of a point on the rim of a non-slipping rolling wheel is a cycloid.